Secondary electric clock.



T. H. WURMB & R. BAUMANN.

SECONDARY ELECTRIC-CLOCK.

APPLICATION FILED AUG. 29, 1910.

1,030,368. Patented June 25,1912.

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H IO-,WASHINGTON D c T. H. WURMB & R. BAUMANN.

SECONDARY ELECTRIC CLOCK. APPLICATION FILED AUG. 29, 1910.

Patented June 25, 1912.

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liiml iiiii UNITED STATES PATENT OFFICE.

THEODORE I-I. WURMB AND ROBERT BAUMANN, OF ST. LOUIS, MISSOURI, ASSIGNORS TO NATIONAL CLOCK & ELECTRIC MANUFACTURING 00., OF ST. LOUIS, MISSOURI,

A CORPORATION OF MISSOURI.

SECONDARY ELECTRIC CLOCK.

Specification of Letters Patent.

Patented June 25, 1912.

Application filed. August 29, 1910. Serial No. 579,459.

To all whom it may concern Be it known that we, THEODORE H. WURMn and ROBERT BAUMANN, citizens of the United States, and residents of St. Louis, Missouri, have invented certain new and useful Improvements in Secondary Electric Clocks, of which the following is a specification containing a full, clear, and exact description, reference being had to the accompanying drawings, forming a part iereof.

Our invention relates to secondary electric clocks, and consists in the novel construction, combination and arrangement of parts hereinafter described and pointed out in the claim.

The object of our present invention is to improve upon the construction shown and described in our previous U. S. Patents No. 679,546 and No. 682,377, dated respectively July 30, 1901 and September 10, 1901, whereby the clock movement will be greatly simplified and the operation be more positive and reliable.

Our improved secondary electric clock movement is principally adapted to use in post-clocks, sign-clocks and system-clocks.

Post and sign clocks, if operated by an ordinary electro-magnet, will require excessive electric power, on account of the unavoidable long throw of the armature, but by the use of our improved electro-magnet (previously patented to us in our said Patent No. 682,377) which we have now improved and simplified, this defect has been obviated.

In the drawings: Figure 1 is a plan view of our improved electric clock movement; Fig. 2 is a side elevation of the same; Fig. 3 is a sectional plan view, the section being taken on line 3-3 of Fig. 2; Fig. 4: is a sectional front elevation, the section being taken on the line 4.-1 of Fig. 2 looking in the direction indicated by the arrow; and Fig. 5 is a detail section taken on the line 55 of Fig. 1.

The numerals 1 and 2 indicate the two vertical frame-plates, the plate 1 being the front frame-plate and the plate 2 the rear frame-plate. The two bolts 1 and 5 carry the yoke 6- 0f the electro-magnet, and the cores 8 and 7 of said magnet have their lower ends secured to said yoke. Said cores are wound and connected in the usual manner. The improved armature 9 is pivoted at one end to said core 8 and its opposite end is provided with a recess 10 in its underside for the purpose of permitting the greater body of metal in said armature end to pass below the free upper end of the pole. This arrangement of the armature and the pole reduces the air-gap to a minimum throughout the entire movement of the armature, thereby requiring a comparatively small amount of electric current, and equaling the pull of the magnet throughout its range of motion, and resulting in the highest possible efficiency. The effects of the residual current are counteracted by the spring-actuated pin 11 which is mounted to slide vertically within a hole 12 formed in said core 7. This pin, when depressed by the closing of the armature, compresses its spring 13, and the power of this spring acts to quickly detach the armature upon cutting out the coils of the magnet by the action of the contact attachment of the master-clock (not shown). A spring pawl 14, made of a fiat piece of L-shaped, resilient metal has its inner end fixed to the rear side of the said armature 9 by means of suitable screws or rivets 15, so that the main part of its body will be free to bend laterally, and so that one of its arms 16 will project free inwardly at the free end of said armature. (See Fig. 4.) A ratchet wheel 17, having preferably eight teeth, is fixed upon a vertical shaft 18 adj acent the inner end of the projecting arm 16 of said. spring pawl 14. The inner end of said arm 16 is curved outwardly, so that the said pawl maycontact more closely with the teeth of said ratchet wheel. Said vertical shaft 18 is mounted in bearings formed in brackets 19 projecting inwardly from the rear frame-plate 2. The said shaft 18, in addition to carrying the said ratchet wheel 17 has fixed upon it a worm 20, and also an additional ratchet wheel 21, which latter is located intermediately of the said worm and the first mentioned ratchet wheel 17. Said worm 20 drives a worm wheel 21 fixed on the minute hand shaft (or half minute hand shaft) or center shaft 22, which latter extends through a bearing in the rear frameplate 2 and projects a suitable distance exterior of same to receive and carry the usual reducing gear train 23 for the hour hand, there being a portion of said train mounted on a stud 24 projecting from the rear face of said rear frame-plate. The inner end of the shaft 22 is mounted in a bearing formed in the non-magnetic post 25 which projects inwardly from the yoke 6 between the spools or coils of the electro-magnet. The preferable ratio of movement between said worm 20 and said worm wheel 21 is one to fifteen, so that with half minute contacts from the master-clock the armature 9 would make one hundred and twenty strokes per hour, the said ratchet wheel 17 having eight teeth and reducing the movement of the said worm 20 to fifteen revolutions per hour while the said worm wheel 21 and the minute shaft make one revolution. 2f indicates a flat stop spring, the outer end of which is fixed to the rear frame-plate in such a manner that the inner end of said stop spring engages the teeth of said ratchet wheel 17, and prevents same from being carried backward by the friction between said ratchet wheel and the said spring pawl 14 of the armature. Referring again to the additional ratchet wheel 21 on the shaft 18, it will be observed that its teeth are the reverse of those of the ratchet wheel 17. 26 indicates an L-shaped brake-dog which projects laterally from the armature 9, so that the vertical arm of said dog will temporarily engage the teeth of said ratchet wheel 21, and lock it and its shaft 18 against backward movement just as the armature approaches the end of its stroke, thereby making it impossible for the hands to jump more than one step at a time. Said brake-dog 26 is preferably formed of a fiat piece of steel bent into L-shape and secured to the outer side of the said armature by means of screws or rivets, so that its vertical arm will engage the tooth of said ratchet wheel 21 only when the armature approaches the limit of its stroke. (See Fig. 5.)

The construction above described is all the important elements necessary for use in a singlefaced clock, but as the drawings show a duplication of parts for a doublefaced clock, we will now describe said duplicate parts and the necessary connecting and operating gearing between the parts just described and those of the additional ace.

An additional vertical shaft 27 (a duplicate of the shaft 18) is mounted in bearings formed in brackets 28 projecting inward from the frame-plate 1, and said shaft 27 carries a worm 29 which drives a worm wheel 30 on the minute hand shaft 31 of the second face mechanism. The said shaft 31 extends through a bearing or opening in the frame-plate 1 and is of sufiicient length to carry the minute hand (not shown), as well as the usual reducing gearing 32 for the hour hand, there being a portion of said gearing mounted on a stud 33 projectingfrom the front face of said frame-plate 1. The inner end of the shaft 31 is mounted in a bearing formed in the non-magnetic post 25, previously described. The said shaft 27 is driven from the shaft 18 by means of a gear wheel 34 on the shaft 18 meshing with a similar gear wheel 35 on the shaft 27.

)Ve provide an improved means for securing the clock movement to the clock dial (not shown direct,) thereby avoiding the expense of the usual supporting rods, braces or brackets, as well as avoiding the casting of shadows upon the dial when same is illuminated from the inside at night.

The following is a description of our improved mounting device: A dial clampingbracket, composed in the present instance of a rectangular plate 36 secured to one of the frame-plates (the plate 1 in the construction shown) by means of the studs 37; said plate 36 having a central hole for the passage therethrough of the minute hand shaft 31 and the hour hand sleeve 38, a sleeve 39 having its inner end integral with or fixed to said plate 36 so that the hole in said sleeve registers with the hole in said plate 36, the outer end of said sleeve 38 being screw threaded, and a suitable nut 39 (which is circular as shown, but which may be square or hexagonal) mounted on said threaded free end of said sleeve 39.

The operation is as follows: In the construction above described the clock movement is supported in position by the dial, said dial, of course, having the usual hole, and the threaded hub 38 is passed through said hole in said dial so that the threaded end of said hub projects outside of the dial,

then the nut 39 is applied to said threaded hub, clamping the dial securely between.

said nut and the bracket-plate 36, and thus firmly supporting the movement in position on the dial. Of course, if the dial is glass, suitable rubber washers should be used in the usual manner and for the usual purpose of protecting the dial in clamping it between the said nut and the said plate 36. When the armature is attracted, the lower end of the arm 16 of the spring pawl 11 will be forced into contact with the tooth of the ratchet wheel 17 which is directly beneath said arm 16, and the said ratchet wheel will be moved one step forward, carrying with it the shaft 18, worm 20, reversed tooth ratchet wheel 21 and the gear wheel 34. By reason of the peculiar construction and L-shape of the said spring pawl 14, it performs practically the function of two spring pawls; or, in other words, it is a double action pawl, its main body portion being free to give when pressed away from the armature 9, and the arm 16 of said spring pawl is free to give to a greater extent as required for it to follow the arc of movement of the ratchet wheel 17 Movement is transmitted from the said worm 20 to the worm wheel 21 thereby moving the minute hand shaft 22 and the hour hand train of gearing 23, thus imparting movement to the clock hands of one dial. From the gear wheel 34 movement is communicated to the gear wheel to drive the lands of the opposite dial. The said gear wheel 35 moves its shaft 27 and worm 29 which latter imparts movement to the corresponding minute hand shaft 31. The corresponding movement of the hour hand reducing gearing 32 is thus also brought about. It will be impossible for the hands to jump more than one step when the armature is attracted because of the fact that the Lshaped brake-dog 26 will have temporarily engaged the teeth of the said ratchet wheel 21, and have locked it against backward movement just as the armature approached the end of its stroke. When the armature is released, the same will be quickly detached by the action of the spring 13 in the core 7 forcing outward the pin 11, and the outward movement of the armature, of course, detaches the spring pawl 14 from the teeth of the ratchet wheel 17 and also detaches the brake-dog 26 from the teeth of the ratchet wheel 21, thereby leaving the parts in position to be again moved by the action of the armature. As the armature is forced outward by said spring 13, the flat stop spring 25 being in permanent engagement with the said ratchet wheel 17, prevents the same from being carried backward by the friction between the said ratchet wheel and the said spring pawl 14:.

Vi e claim:

In an electric clock, an electro-magnet, an armature, an L-shaped spring-pawl hav ing one of its arms fixed to and carried by the armature so that the pawl will be moved bodily therewith but permit the free arm to give toward and from said armature and also to be warped, a shaft to be rotated, a pair of oppositely arranged ratchet wheels, one of which is positioned to be actuated by said free arm of said spring-pawl,

and a rigid member also carried and actu ated by the armature and arranged to contact with the other ratchet wheel.

In testimony whereof, we have signed our names to this specification, in presence of two subscribing witnesses.

THEODORE H. XVURMB. ROBERT BAUMANN. Vitnesses E. L. lVALLAon, N. G. BUTLER.

Copies of this patent may be obtained for five cents each,'by addressing the Commissioner of Patents,

Washington, D. C. 

